I upgraded my Ubuntu machine to the latest LTS build last week and was quickly disappointed that my terminal no longer had opacity. No matter what I did, the window would just appear as a solid color. I tried googling, etc. but couldn’t find any solution online.
I gave up and ended up editing my background profile and fixed it totally by accident. I switched my background from transparent to a solid color and then back to transparent and voilà! transparency was back.
I’m not 100% sure why the issue happened in the first place-anyone?-but I hope that someone finds this fix out there.